# Highly scientific FOC Simulation
**URL:** https://community.simplefoc.com/t/highly-scientific-foc-simulation/3901
**Category:** Uncategorized
**Created:** [September 19, 2023, 2:10pm UTC](https://community.simplefoc.com/t/highly-scientific-foc-simulation/3901 "2023-09-19T14:10:18Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@Candas1](https://community.simplefoc.com/u/Candas1)
#### Post date: [September 19, 2023, 2:10pm UTC](https://community.simplefoc.com/t/highly-scientific-foc-simulation/3901/1 "2023-09-19T14:10:18Z")
Here is the spammer again.
Wanted to share something I used last few days for learning purpose.
It’s clearly not a scientific tool but gives a good intuition about how FOC works.
It’s a very simplified FOC simulation in a [gsheet](https://docs.google.com/spreadsheets/d/1yLXF6wKdk0xLEGpTAMmxBcFIUjrvI8vpThAcZM2Sszo/copy) 😂
In the **Phase current to DG** tab:
- If you enter a different gain for phase A (e.g. 1,1), this makes D/Q currents wobbly, the PIs will have to compensate this. With good hardware I guess it shouldn’t happen.
- If you enter a delay (e.g. 0,1), it introduces a lag between the rotor angle and the sensor angle, this shows not measuring the current and the position at the same time can introduce an error in D and Q (a little) current measurement, reducing the efficiency.
in the **DQ current to PWM** tab:
- increasing D current (e.g. 0,5) not only introduces a shift in phases, but also increases the amplitude
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### Author:  [@Candas1](https://community.simplefoc.com/u/Candas1)
#### Post date: [September 19, 2023, 3:59pm UTC](https://community.simplefoc.com/t/highly-scientific-foc-simulation/3901/2 "2023-09-19T15:59:04Z")
And another more advanced [motor simulator](https://github.com/markisus/motor_sim#bldc-and-pmsm-simulator)
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### Author:  [@Candas1](https://community.simplefoc.com/u/Candas1)
#### Post date: [September 19, 2023, 6:11pm UTC](https://community.simplefoc.com/t/highly-scientific-foc-simulation/3901/3 "2023-09-19T18:11:27Z")
You must be thinking, my phase currents don’t look like that. Fair point, let’s add some noise:
Someone proposed to filter the phase current, great idea !!! let’s do it:
It looks much better now. But why did the D current increase ? Oh no we introduced lag !!!
The same would happen if filtering Alpha and Beta… What about filtered the D and Q currrents ?
Ah, much better !!!
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### Author:  [@Candas1](https://community.simplefoc.com/u/Candas1)
#### Post date: [September 19, 2023, 7:05pm UTC](https://community.simplefoc.com/t/highly-scientific-foc-simulation/3901/4 "2023-09-19T19:05:32Z")
But my sensor is slow, it’s not updating often!!!
Oh no !!! D axis current is off and wobbly! More work for the PI controller…
Lukily we can use sensor smoothing !!!
OK I stop bothering you 😂
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### Author:  [@o\_lampe](https://community.simplefoc.com/u/o_lampe)
#### Post date: [September 19, 2023, 7:13pm UTC](https://community.simplefoc.com/t/highly-scientific-foc-simulation/3901/5 "2023-09-19T19:13:56Z")
Very informative and entertaining.
But we need filtering,unless we have stable signals without glitches.
IMHO these glitches are the bigger problem.
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### Author:  [@Candas1](https://community.simplefoc.com/u/Candas1)
#### Post date: [September 19, 2023, 7:16pm UTC](https://community.simplefoc.com/t/highly-scientific-foc-simulation/3901/6 "2023-09-19T19:16:14Z")
Yes I am showing filtering D Q currents works better, that’s what SimpleFOC is doing. But it’s not perfect either…
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### Author:  [@Candas1](https://community.simplefoc.com/u/Candas1)
#### Post date: [September 20, 2023, 5:50am UTC](https://community.simplefoc.com/t/highly-scientific-foc-simulation/3901/7 "2023-09-20T05:50:31Z")
Changing phase C current doesn’t impact Alpha/Beta and D/Q currents, how come ? 🤔
Because Ia+Ib+Ic= 0 (Kirchhoff’s law), only 2 phase currents are enough for FOC.
But why do we even measure 3 currents then ?
In reality, the total of phase currents don’t add up to 0 because of inaccuracies in hardware, and noise during sampling. One of the reasons why it’s useful to have 3 phase currents is that this can be used to slightly reduce the noise by sharing this error between the 3 phase currents:
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### Author:  [@Candas1](https://community.simplefoc.com/u/Candas1)
#### Post date: [September 26, 2023, 8:55am UTC](https://community.simplefoc.com/t/highly-scientific-foc-simulation/3901/8 "2023-09-26T08:55:14Z")
Added different modulation types and the effect of deatime on line to line voltage in the DQ to PWM tab if you are interested:
